1. Field of the Invention
The present invention relates to binoculars provided with an image stabilizing function (image blur correcting function) to reduce image blur caused by hand jiggling or the like.
2. Description of the Related Art
Binoculars are often used while being held in observer's hands, so that providing thereto an image stabilizing function to reduce image blur caused by hand jiggling or the like can improve their usability. The image stabilizing function for the binoculars is achieved by moving (shifting) image stabilizing lenses constituting parts of right and left optical systems with an actuator in a direction orthogonal to an optical axis in which the image blur caused by the hand jiggling or the like is canceled out.
The right and left optical systems arranged right and left in the binoculars have a same configuration, and form optical images that are simultaneously observed through observer's right and left eyes. Therefore, it is necessary to shift the image stabilizing lenses simultaneously and equally in the right and left optical systems.
Japanese Patent Laid-Open Nos. 10-020213 and 10-301035 disclose binoculars in which a lens holding member holding both right and left image stabilizing lenses is guided in two directions orthogonal to an optical axis with a guiding configuration in which a guiding pin formed in one of the lens holding member and a base member is inserted into a hole portion formed in the other one thereof.
In the lens holding member guiding configuration in the binoculars disclosed in Japanese Patent Laid-Open Nos. 10-020213 and 10-301035, a gap is provided between the guiding pin and the hole portion to enable smooth shifting of the lens holding member. However, such a gap allows the lens holding member to be displaced in a direction different from the direction to cancel out the image blur.
In particular, rotation of the lens holding member holding the right and left image stabilizing lenses in a plane orthogonal to the optical axis generates errors in a relative positional relationship in the direction orthogonal to the optical axis between the image stabilizing lenses and other lenses in the right and left optical systems. Such errors cause differences in motion and position of the optical images observed through the right and left optical systems, which brings a feeling of strangeness to an observer.
Moreover, sliding between the guiding pin and the hole portion generates a large sliding friction, and the sliding friction acts on the lens holding member as a driving resistance. Therefore, the guiding configurations disclosed in Japanese Patent Laid-Open Nos. 10-020213 and 10-301035 are disadvantageous configurations for minute drive of the lens holding member (that is, of the image stabilizing lenses).